21539343907 has 2 divisors, whose sum is σ = 21539343908. Its totient is φ = 21539343906.

The previous prime is 21539343871. The next prime is 21539343923. The reversal of 21539343907 is 70934393512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21539343907 - 2²⁷ = 21405126179 is a prime.

It is not a weakly prime, because it can be changed into another prime (21539343937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10769671953 + 10769671954.

It is an arithmetic number, because the mean of its divisors is an integer number (10769671954).

Almost surely, 2^21539343907 is an apocalyptic number.

21539343907 is a deficient number, since it is larger than the sum of its proper divisors (1).

21539343907 is an equidigital number, since it uses as much as digits as its factorization.

21539343907 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 612360, while the sum is 46.

The spelling of 21539343907 in words is "twenty-one billion, five hundred thirty-nine million, three hundred forty-three thousand, nine hundred seven".